380 replies to this topic

[Arno]

As documented on Mark's site, heater and cooling system diagram on the Z22SE as installed in the VX/Speedster:



(See: http://www.verboom.n...ngle=20100411.0 )

The heater circuit return line connects to the back of the thermostat housing and this 'drives' the T-stat opening and also works as the engine bypass circuit when the T-stat is still closed.

Same cooling and heater circulation setup was used on the S1 Elise and rover powered S2's. (Toyota powered S2's still similar, but some small differences)

The early S2 Elises have the identical heater as the VX/Speedster. Later models have a completely different one that can also house an A/C evaporator and has a much larger heater core installed.

Bye, Arno.

[T7Design]

Out of curiosity why did they fit the thermostat just before the pump and not at the outlet point on the head?

[mulletmaster]

And what is the sensor on the main water outlet then?water temp sensor for the dash?

[Arno]

Out of curiosity why did they fit the thermostat just before the pump and not at the outlet point on the head?

This is now a common design feature on many modern engines. Thermostat is on the pump intake side and a bypass system is the 'trigger' for it to open.

In some cases (eg. Toyota 1KR-FE engine) the thermostat operation is even 'reversed' where all ports are 'open' when it's cold (flow will follow the path of least resistance through the bypass) and the bypass circuit is slowly closed off (pump sucking coolant from the radiator) as it heats up.

Some of it is probably packaging/layout driven, but the main reason is that modern engine thermal design doesn't try to stabilise the temperature of the coolant coming OUT of the engine (like a thermostat at the outlet would do), but tries to stabilise the coolant temperature going INTO the engine.

This reduces thermal cycling and distortion issues inside the block and head and is good for longlevity of the engine and headgaskets and such. (if done properly )

Some engines now even use a thermostat setup where the 'bypass' size is as big as the main coolant hose size to not only stabilise the temperatures, but also to try to keep the coolant flow rate at a constant (or at least linear to the rpm's) irrespective if the thermostat is 'open' or 'closed'. These often have thermostat elements with double valves, so when the radiator circuit starts to open it slowly closes off the bypass port at the same time keeping the total flow the same.

Bye, Arno.

[Arno]

And what is the sensor on the main water outlet then?water temp sensor for the dash?

On the 2.2 engine there should be no sensor on the main outlet at the top/back of the cylinder head, only a takeoff with a small hose that feeds back to the top of the coolant expansion tank (to catch/get rid of air bubbles).

The coolant temperature sensor for the ECU (which relays this to the dash) on the 2.2 is in the housing that's bolted to the block where the heater outlet is located on the exhaust side of the block at the gearbox side.

On the turbo engine this is probably different!

Bye, Arno.

[mulletmaster]

Cheers arno, I know the small take off to the exp tank, it's the one that spewed out coolant when I took it off to get at the fuel rail!there is a much fatter pipe just below it tho that has 2 wires going to it(which I acidentally grounded with sparks) so was just wondering what i have blown since I couldn't find any popped fuses!

[slindborg]

Cheers arno, I know the small take off to the exp tank, it's the one that spewed out coolant when I took it off to get at the fuel rail!there is a much fatter pipe just below it tho that has 2 wires going to it(which I acidentally grounded with sparks) so was just wondering what i have blown since I couldn't find any popped fuses!

was it plugged into the header tank? if so that was the level sensor

[Ormes]

It would be great if you could do something with the system. I may hold off sealing my box until this develops futher and take the small increase already offered by the Vanair ebay thing I just installed. Can you build an easily accessible cabin filter into the design Look forward to seeing how this develops. ** Are there any subtle differences between the available space for pipework etc., in the front of an NA vs. Turbo? ** ...as I would hate to think that we get all this working on one car and then can't fit it in another

[Ormes]

T7 I assume you found this http://www.vx220.org...aling-and-mods/ which helps show how its packaged?

[moneyhunster]

Aah a cabin filter, forgot about that, filter out the flys

[T7Design]

Haha, is that actually a problem some of you experience?? @ Ormes, Thanks for the link. There are certainly some helpful pictures to better show how the unit fits and works. The unit looks quite large, does anybody have any rough measurements?

Edited by T7Design, 01 January 2011 - 03:44 PM.

[RacerJo]

Haha, is that actually a problem some of you experience??

It is a problem, i find it out the hard way, reduse also dust and sand.

[Mangham54]

Haha, is that actually a problem some of you experience??

@ Ormes, Thanks for the link. There are certainly some helpful pictures to better show how the unit fits and works. The unit looks quite large, does anybody have any rough measurements?

No measurements... But the fact that there is no filtration element (of any type) means that all manner of sh** flies into the cabin... That and an obligatory bunch of wasps and bees in the middle of the summer seem to reside in the cabin when it's parked up.

A simple filter (that isn't a sock) would be an epic improvement.

[2.2_na]

I had to drive with the windows open today! I had the heater on (lowest level) and after about 20 minutes it was too warm in there, so I turned the heater off and still had to open the windows to get some air in.

[moneyhunster]

I had to drive with the windows open today!

I had the heater on (lowest level) and after about 20 minutes it was too warm in there, so I turned the heater off and still had to open the windows to get some air in.

Show off!

[slindborg]

tbh NOT taking air from the direct stream in the mouth would be a huge step in the right direction of getting less crap in the cabin. Just take the air from the 'back' of the battery/heater compartment rather than having dirty air forced into the OEM airbox would help no end.. I've noticed from simply having the 3" fan on the cabin intake there is some dust but not the level it used to be from the OEM setup, and no wasps/bees anymore

[Paulus H]

T7D, There are 3 topics on the first page of the mods secition of this site. I think this shows it would be worth your time coming up with a no brainer solution. You will make more sales in the winter, not wishing to hurry you or anything.... Paul

[T7Design]

Hi Guys, I am expecting the heater from MoneyHunster to come through soon and I will be able to see what size rads can fit and whether I can squeeze in two fans to give it a bit more poke. It would be really helpful if anybody could pop round so I may get a of feel of the original system and to also see how much of an improvement an prototype system could make, if anybody is interested I can do them a free heater for their troubles! I would require you to pop around twice, once for measuring and a 2nd time for fitting and trials. Regards, Adam P.S. I forgot to add I am based in Exeter!

Edited by T7Design, 04 January 2011 - 09:47 PM.

[moneyhunster]

Wish I was closer! Any news on my modular one? Mine went off on friday, bloody post!

[Exmantaa]

tbh NOT taking air from the direct stream in the mouth would be a huge step in the right direction of getting less crap in the cabin.

Just take the air from the 'back' of the battery/heater compartment rather than having dirty air forced into the OEM airbox would help no end..

I've noticed from simply having the 3" fan on the cabin intake there is some dust but not the level it used to be from the OEM setup, and no wasps/bees anymore

I still want to try a VW polo heater that just sucks air from under the bonnet with the front scoops blocked off.